The focus of this proposal is the quantification of clinically-evident risk factors for age-related proximal femur fractures as they occur in a community. The results of this study will provide the data needed to design an effective prevention program, by delineating the high-risk patient groups who could most profit from detailed assessment and subsequent prophylactic measures. These data are not presently available and, as a result, organized preventive efforts are essentially at a standstill. The specific factors to be studied have been suggested by previously published research or identified in preliminary studies here. The epidemiologic case-control study proposed will help clarify which of the factors are significantly associated with hip fractures, which have the greatest potential impact on community hip fracture rates, which occur long enough before the fracture to permit effective intervention, and what proportion of the hip fracture population can be identified through these factors. The present proposal is also the key to future epidemiologic studies of age-related fractures in the community. Rochester is an ideal setting for this type of research because most of the biases that bedevil case-control studies elsewhere can be obviated here. Medical care for the population of Olmsted County, Minnesota, is almost entirely provided by the Mayo Clinic and the Olmsted Medical Group and their affiliated hospitals. The records of these institutions and other providers have been assembled into a single diagnostic retrieval system and comprise a unique resource for population-based epidemiologic studies. Thus we can identify complete incidence cohorts of patients with hip fractures and can find matched controls who are representative of the general population. Exposure data are available from accurate and detailed contemporary medical records of long duration.